U.S. patent number 4,883,718 [Application Number 07/159,850] was granted by the patent office on 1989-11-28 for flexible copper-clad circuit substrate.
This patent grant is currently assigned to Mitsui Toatsu Chemicals, Inc.. Invention is credited to Saburo Kawashima, Masahiro Ohta, Hideaki Oikawa, Yoshiho Snobe, Shoji Tamai, Akihiro Yamaguchi.
United States Patent |
4,883,718 |
Ohta , et al. |
November 28, 1989 |
Flexible copper-clad circuit substrate
Abstract
This invention relates to flexible copper-clad circuit
substrates where copper foil is directly and firmly jointed with a
polyimide film. Polyimide used is obtained conventionally by
reacting diamine components including 3,3'-diaminobenzophenone,
1,3-bis(3-aminophenoxy)-bezene, 4,4'-bis(3-aminophenoxy)biphenyl,
2,2-bis[4-(3-aminophenoxy)-phenyl]propane,
2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane,
bis[4(3-aminophenoxy)phenyl] sulfide, bis[4-(3-aminophenoxy)phenyl]
ketone and bis[4-(3-aminophenoxy)phenyl] sulfone, with
tetracarboxylic acid dianhydride including pyromellitic
dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride,
3,3',4,4'-biphenyl tetracarboxylic dianhydride and
bis(3,4-dicarboxyphenyl) ether dianhydride, in organic solvent, and
by thermally or chemically imidizing resultant polyamic acid.
Polyimide thus obtained has relatively lower melt viscosity and is
flowable at high temperatures. Therefore, the copper foil and the
polyimide film were assembled, pressed by heating under pressure
and further cured to afford the flexible copper-clad circuit
substrates having the polyimide film firmly jointed with the copper
foil.
Inventors: |
Ohta; Masahiro (Yokohama,
JP), Kawashima; Saburo (Yokosuka, JP),
Snobe; Yoshiho (Yokohama, JP), Tamai; Shoji
(Yokohama, JP), Oikawa; Hideaki (Yokohama,
JP), Yamaguchi; Akihiro (Kamakura, JP) |
Assignee: |
Mitsui Toatsu Chemicals, Inc.
(Tokyo, JP)
|
Family
ID: |
26360888 |
Appl.
No.: |
07/159,850 |
Filed: |
February 5, 1988 |
PCT
Filed: |
June 30, 1986 |
PCT No.: |
PCT/JP86/00334 |
371
Date: |
February 05, 1988 |
102(e)
Date: |
February 05, 1988 |
PCT
Pub. No.: |
WO88/00428 |
PCT
Pub. Date: |
January 14, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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44028 |
Jun 13, 1986 |
4847349 |
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Foreign Application Priority Data
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Feb 12, 1985 [JP] |
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60-23520 |
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Current U.S.
Class: |
428/458; 428/901;
528/176; 564/430; 428/473.5; 528/125; 528/185 |
Current CPC
Class: |
B32B
15/08 (20130101); H05K 1/0346 (20130101); H05K
3/022 (20130101); Y10S 428/901 (20130101); Y10T
428/31721 (20150401); Y10T 428/31681 (20150401) |
Current International
Class: |
B32B
15/08 (20060101); H05K 1/03 (20060101); H05K
3/02 (20060101); B32B 015/08 (); B32B 027/06 () |
Field of
Search: |
;428/458,473.5,901
;528/125,185,176 ;564/130 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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52-35281 |
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Mar 1977 |
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JP |
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58-155790 |
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Sep 1983 |
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JP |
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58-157190 |
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Sep 1983 |
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JP |
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58-190092 |
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Nov 1983 |
|
JP |
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59-76451 |
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May 1984 |
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JP |
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59-168030 |
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Sep 1984 |
|
JP |
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60-243120 |
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Dec 1985 |
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JP |
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60-258228 |
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Dec 1985 |
|
JP |
|
143478 |
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Jul 1986 |
|
JP |
|
Other References
Yasuo et al., English Translation of Japanese Patent No. 58-157190,
Sep. 19, 1983. .
Shunichi et al., English Translation of Japanese Patent No.
59-76451, May 1, 1984. .
Susumu, English Translation of Japanese Patent No. 59-168030, Sep.
21, 1984. .
English Translation of Japanese Patent No. 52-35281; 3/1977, claim.
.
English Translation of Japanese Patent No. 58-190092, 11/1983,
claim. .
English Translation of Japanese Patent No. 58-155790, 9/1983. .
English Translation of Japanese Patent No. 60-243120, 12/1985,
claims 1-5. .
English Translation of Japanese Patent No. 60-258228, 12-1985.
.
Bell, Journal of Polymer Science: Polym. Chem. Ed., 14, 225-235,
2275-2292 (1976)..
|
Primary Examiner: Herbert; Thomas J.
Attorney, Agent or Firm: Fisher, Christen & Sabol
Parent Case Text
This is a continuation-in-part of U.S. application Ser. No.
044,028, filed on June 30, 1986 now U.S. Pat. No. 4,847,349.
Claims
We claim:
1. A flexible copper-clad circuit substrate comprising a
high-temperature flowable polyimide film directly jointed with
copper foil in the absence of adhesive therein between, the
polyimide having recurring units of the formula: ##STR21## wherein
R is a tetra-valent radical selected from the group consisting of a
aliphatic radical having 2 and more carbons, a cycloaliphatic
radical, monoaromatic radical, a fused polycyclic radical and a
polycyclic aromatic radical wherein the aromatic radicals are
linked to one another directly or via a bridge member.
2. A flexible copper-clad circuit substrate comprising a
high-temperature flowable polyimide film directly jointed with a
copper foil in the absence of an adhesive, the polyimide has the
recurring units of the general formula: ##STR22## wherein R is a
tetra-valent radical selected from the group consisting of an
aliphatic radical having 2 or more carbons, a cycloaliphatic
radical, monoaromatic radical, a fused polycyclic radical and a
polycyclic aromatic radical wherein the aromatic radicals are
linked to one another directly or via a bridge member, said
flexible copper-clad circuit substrate having been prepared by the
process comprising placing a film or powder of said polyimide on
said copper foil, pressing said polyimide foil or powder at
50.degree. to 400.degree. C. under a pressure of 1 to 1,000
kg/cm.sup.2 and curing said pressed polyimide film at 100.degree.
to 400.degree. C.
3. A flexible copper-clad substrate comprising a high-temperature
flowable polyimide film directly jointed with a copper foil in the
absence of an adhesive, the polyimide has the recurring units of
the general formula: ##STR23## wherein R is a tetra-valent radical
selected from the group consisting of an aliphatic radical having 2
or more carbons, a cycloaliphatic radical, monoaromatic radical, a
fused polycyclic radical and a polycyclic aromatic radical wherein
the aromatic radicals are linked to one another directly or via a
bridge member, said flexible copper-clad circuit substrate having
been prepared by the process comprising placing a solution of
polyamic acid onto the copper foil, the polyamic acid solution
having a viscosity of 1,000 to 300,000 centipoises, and heating the
copper foil and the layer of said polyamic acid solution at
100.degree. to 400.degree. C., whereby the solvent is removed and
said polyamic acid is converted said polyimide.
Description
FIELD OF THE INVENTION
The present invention relates to flexible copper-clad circuit
substrates and particularly related to the flexible copper-clad
circuit substrates which are excellent in high-temperature
stability and high-temperature adhesion.
BACKGROUND OF THE INVENTION
The flexible copper-clad circuit substrates which are used for
printed circuit substrates of electronic instruments recently have
a serious problem of increase in heat generation accompanied by
rise up of package density and wiring pattern density. Thus an
important subject is to improve high-temperature stability of the
substrates. High-temperature resin which substitutes conventional
epoxy resin, includes heat-stable epoxy, polyamide imide,
polybenzimidazole, silicone, and polyimide resin. These resins,
however, are not always satisfactory to the peel strength to copper
foil. Among these resins, polyimide in particular is excellent in
high-temperature stability and electrical characteristics, and has
increasingly been interested as the materials for electrical
insulation. Polyimide, however, has poor bonding strength to metals
and requires adhesives to bond the copper foil when polyimide is
used for the base film of copper-clad circuit substrates. In spite
of good high-temperature stability, insufficient thermal stability
of the adhesives inhibits the full utilization of essential
high-temperature stability of polyimide. Therefore, polyimide is
extensively required which is excellent in high-temperature
stability and adhesive strength to metals.
The object of this invention is to provide the high-temperature
stable and flexible copper-clad circuit substrates which cause no
reduction of adhesive strength during and after use at high
temperatures and require no adhesives.
DETAILED DESCRIPTION OF THE INVENTION
The inventors studied hard to solve these problems and achieved the
invention by finding the fact that polyimide prepared from
particular diamine and tetracarboxylic acid dianhydride was
flowable at high temperatures as well as excellent in high
temperature stability and bonding strength to the copper foil.
High temperature flowable polyimide in this invention means
polyimide which has melt viscosity of 5.times.10.sup.5 poises and
less at 400.degree. C. and shear rate of 10.sup.3 l/second by the
flow tester of the Society of Polymer Science model (Shimadzu
Seisakusho CFT-500) with a nozzle of 0.1 cm in diameter and 1 cm in
length. Polyimide in this category is prepared from the following
diamine and tetracarboxylic acid dianhydride.
Polyimide and/or its polyamic acid precursor for use in this
invention are not restricted in particular on the method of their
preparation. They can normally be prepared by polymerizing various
diamine with tetracarboxylic acid dianhydride in organic
solvents.
Diamine for use in this method includes 3,3'-diaminobenzophenone,
1,3-bis(3-aminophenoxy)benzene, 4,4'-bis(3-aminophenoxy)-biphenyl,
2,2-bis[4-(3-aminophenoxy)phenyl]propane,
2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexfluoropropane,
bis[4-(3aminophenoxy)-phenyl]sulfide,
bis[4-(3-aminophenoxy)phenyl]ketone and
bis[4-(3-amino-phenoxy)phenyl]sulfone. These are used singly or in
mixtures of the two or more.
Tetracarboxylic acid dianhydride to be reacted with diamine has the
following formula(I): ##STR1## (where R is a tetra-valent radical
selected from the group consisting of aliphatic radical having 2
and more carbons, cycloaliphatic radical, monoaromatic radical,
condensed polyaromatic radical, and non condensed polyaromatic
radical wherein aromatic radicals are mutually connected with a
bond or a crosslinking function).
The dianhydride includes, for example, ethylene tetracarboxylic
dianhydride, cyclopentane tetracarboxylic dianhydride, pyromellitic
dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride,
2,2',3,3'-benzophenone tetracarboxylic dianhydride,
3,3',4,4'-biphenyl tetracarboxylic dianhydride, 2,2'3,3'-biphenyl
tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane
dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride,
bis(3,4-dicarboxyphenyl)ether dianhydride,
bis(3,4-dicarboxyphenyl)sulfone dianhydride,
1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride,
bis(2,3-dicarboxyphenyl)methane dianhydride,
bis(3,4-dicarboxyphenyl)methane dianhydride, 2,3,6,7-naphthalene
tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic
dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride,
1,2,3,4-benzene tetracarboxylic dianhydride, 3,4,9,10-perilene
tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic
dianhydride and 1,2,7,8-phenanthrene tetracarboxylic dianhydride.
These are used singly or in mixtures of two or more.
Particularly preferred tetracarboxylic acid dianhydride is
pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic
dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride and
bis(3,4-dicarboxyphenyl)ether dianhydride.
Polyamic acid precursor of polyimide is normally prepared in the
organic solvents.
Organic solvents include, for example, N-methyl-2-pyrrolidone,
N,N-dimethylacetamide, N,N-dimethylformamide,
1,3-dimethyl-2-imidazolidinone, N,N-diethylacetamide,
N,N-dimethyl-methoxyacetamide, dimethyl sulfoxide, pyridine,
dimethyl sulfone, hexamethylphosphoramide, tetramethylurea,
N-methylcaprolactam, tetrahydrofuran, m-dioxane, p-dioxane,
1,2-dimethoxyethane, bis(2-methoxyethyl)ether,
1,2-bis(2-methoxyethoxy)ethane and
bis[2-(2-methoxyethoxy)ethyl]ether. These solvents are used singly
or in mixtures of two or more.
Reaction temperature is normally 200.degree. C. or less and
preferably 50.degree. C. and less. Reaction pressure is not
restricted in particular and the reaction can satisfactorily
conducted at atmospheric pressure.
Reaction time depends upon type of solvents, reaction temperature,
diamine and acid dianhydride applied and is normally carried out
enough to complete the formation of polyamic acid. Normally 4-24
hours is sufficient.
Corresponding polyimide can be obtained from polyamic acid by
imidizing thermally at 100.degree.-400.degree. C. or by use of
dehydrating agent such as acetic anhydride.
For example, bis[4-(3-aminophenoxy)phenyl]sulfide is reacted in the
organic solvent with tetracarboxylic acid dianhydride having the
formula (I): ##STR2## (where R is the same as above) to give
polyamic acid having recurring units of the formula (II): ##STR3##
(where R is the same as above).
Polyamic acid thus obtained is imidized to give polyimide having
recurring units of the formula (III): ##STR4## (where R is the same
as above).
In the present invention, following polyimide is preferably used in
particular.
(1) Polyimide which is derived from 3,3'-diaminobenzophenone and
tetracarboxylic acid dianhydride having the formula (I): ##STR5##
(where R is the same as above) and which has recurring units of the
formula (IV): ##STR6## (where R is the same as above).
(2) Polyimide which is derived from
4,4'-bis(3-aminophenoxy)biphenyl and tetracarboxylic acid
dianhydride having the formula (I): ##STR7## (where R is the same
as above) and which has recurring units of the formula (V):
##STR8## (where R is the same as above).
(3) Polyimide which is derived from
2,2-bis[4-(3-aminophenoxy)phenyl]propane and tetracarboxylic acid
dianhydride having the formula (I): ##STR9## (where R is the same
as above) and which has recurring units of the formula (VI):
##STR10## (where R is the same as above).
(4) Polyimide which is derived from
2,2-bis[4-(3-aminophenoxy)-phenyl]-1,1,1,3,3,3-hexafluoropropane
and tetracarboxylic acid dianhydride having the formula (I):
##STR11## (where R is the same as above) and which has recurring
units of the formula (VII): ##STR12## (where R is the same as
above).
(5) Polyimide which is derived from
bis[4-(3-aminophenoxy)phenyl]ketone and tetracarboxylic acid
dianhydride having the formula (I): ##STR13## (where R is the same
as above) and which has recurring units of the formula (VIII):
##STR14## (where R is the same as above).
(6) Polyimide wich is derived from
bis[4-(3-aminophenoxy)phenyl]sulfide and tetracarboxylic acid
dianhydride having the formula (I): ##STR15## (where R is the same
as above) and which has recurring units of the formula (IX):
##STR16## (where R is the same as above).
(7) Polyimide which is derived from
bis[4-(3-aminophenoxy)phenyl]sulfone and tetracarboxylic acid
dianhydride having the formula (I): ##STR17## (where R is the same
as above) and which has recurring units of the formula (X):
##STR18## (where R is the same as above).
(8) Polyimide which is derived from 1,3-bis(3-aminophenoxy)benzene
and tetracarboxylic acid dianhydride having the formula (I):
##STR19## (where R is the same as above) and which has recurring
units of the formula (XI): ##STR20## (where R is the same as
above).
The adhesion between high temperature flowable polyimide of this
inventin and the copper foil is performed by use of (1) polyimide
or (2) polyamic acid precursor of polyimide.
(1) When polyimide is used, polyamic acid is thermally or
chemically dehydrated in advance to obtain polyimide in the form of
film or powder. Polyimide film can also be made by calender rolling
the powder. The film or powder is put on the copper foil, pressed
at 50.degree.-400.degree. C. under pressure of 1-1,000 kg/cm.sup.2
and cured at 100.degree.-400.degree. C. to give the flexible
copper-clad circuit substrates.
(2) When polyamic acid precursor of polyimide is used, the polyamic
acid solution is applied on the copper foil and heated at
100.degree.-400.degree. C., preferably at 200.degree.-300.degree.
C. to remove the solvents and convert polyamic acid to more stable
polyimide.
The polyamic acid solution is required to have optimum viscosity so
that desired thickness of the coated film can be obtained by given
application methods. Preferred viscosity is 1,000-300,000
centipoises and concentration can also be adjusted by the organic
solvents used. Coating should be made as uniform as possible and
can be performed with bar coaters or doctor blades.
Besides, in the thermal conversion of polyamic acid to polyimide,
also preferred is heating under pressure of 1-1,000 kg/cm.sup.2,
preferably 1-50 kg/cm.sup.2. Peel strength of the copper foil with
polymer film can be further reinforced by increasing the
pressure.
In addition, the polyimide layer of flexible copper-clad circuit
substrates in this invention is flowable at high temperatures, and
thus these substrates are also characterized by the ability of
hot-bonding with other metal substrates.
SPECIFIC EXAMPLES
The invention will be illustrated further with respect to the
following examples. Inherent viscosity in these Examples was
measured at 35.degree. C. in 0.5 g/100 ml N,N-dimethylacetamide
solution. Rotational viscosity was measured at 25.degree. C. with a
high viscosity rotor of model B viscometer.
Melt viscosity was measured at various temperatures and pressures
with an nozzle of 0.1 cm in diameter and 1 cm in length, by use of
the Society of Polymer Science Model flow tester (Shimadzu
Seisakusho CFT-500).
In addition, peel strength of the copper foil on the copper-clad
circuit substrates was measured in accordance with JIS C-6481.
EXAMPLE 1
In a reaction vessel with a stirrer, reflux condenser and nitrogen
inlet tube, 53.0 grams (0.25 mol) of 3,3'-diaminobenzophenone was
dissolved into 240 ml of N,N-dimethylacetamide. The resultant
solution was added with 78.6 grams (0.244 mol) of
3,3',4,4'-benzophenone tetracarboxylic dianhydride powder and
stirred at 10.degree. C. for 24 hours. The polyamic acid thus
obtained had inherent viscosity of 0.59 dl/g and rotational
viscosity of 32,000 cps. The solution was uniformly coated with the
doctor blade on the electrolytic copper foil having 35 .mu.m in
thickness.
The coated copper foil was heated for an hour each at 100.degree.
C., 200.degree. C. and 300.degree. C. to give the copper-clad
circuit substrates. Thickness of the coated film was about 50
.mu.m. Peel strength of the copper foil of the copper-clad circuit
substrates was 3.5 kg/cm at the room temperature (25.degree. C.).
The same value was obtained by the solder heat resistance test for
180 seconds at 180.degree. C. or 300.degree. C.
In addition, a part of the polyamic acid solution was heated at
100.degree. C. to give polyimide powder having melt viscosity of
2,900 poises at 330.degree. C. and shear rate of 10.sup.3
l/second.
EXAMPLE 2
The electrolytic copper foil having 35 .mu.m in thickness was put
on a steel drum for continuous film casting and the polyamic acid
solution obtained in Example 1 was continuously casted with the
doctor blade. The steel drum was gradually heated from 100.degree.
C. to 250.degree. C. and finally the foil was pressed through rolls
at 300.degree. C. to give the copper-clad circuit substrates
continuously. Thickness of the coated film was about 55 .mu.m. Peel
strength of the copper foil of the substrates was 3.7 kg/cm at the
room temperature (25.degree. C.). The same value was obtained by
the solder heat resistance test for 180 seconds at 260.degree. C.
or 300.degree. C.
EXAMPLE 3
A reaction vessel with a stirrer, reflux condenser and nitrogen
inlet tube was charged with 41.0 grams (0.1 mol) of
2,2-bis[4-(3aminophenoxy)phenyl]propane and 200 ml of
N,N-dimethylacetamide and cooled to about 0.degree. C. Under
nitrogen atmosphere 21.8 grams (0.1 mol) of pyromellitic
dianhydride powder were added and stirred for 2 hours at about
0.degree. C. The temperature of the reaction mixture was raised to
the room temperature and stirred for about 20 hours under nitrogen
atmosphere. The polyamic acid solution thus obtained had inherent
viscosity of 1.5 dl/g and rotational viscosity of 56,000 cps.
The solution was applied on the electrolytic copper foil having 35
.mu.m in thickness. The coated copper foil was heated for an hour
each at 100.degree. C., 200.degree. C. and 300.degree. C. to give
the copper-clad circuit substrate. Thickness of the coated film was
125 .mu.m. Peel strength of the copper foil was 3.8 kg/cm at the
room temperature (25.degree. C.). The same value was obtained by
the solder heat resistance test for 180 seconds at 180.degree. C.
or 300.degree. C.
Besides the polyimide powder obtained by the same procedure as
Example 1 had melt viscosity of 4,900 poises at 380.degree. C. and
shear rate of 10.sup.3 1/second.
EXAMPLE 4
A reaction vessel with a stirrer, reflux condenser and nitrogen
inlet tube was charged with 41.0 grams (0.1 mol) of
2,2-bis[4-(3-aminophenoxy)phenyl]propane and 219.6 grams of
N,N-dimethylacetamide. Under nitrogen atmosphere and at the room
temperature, 31.6 grams (0.098 mol) of 3,3',4,4'-benzophenone
tetracarboxylic dianhydride was added as dry solids by small
portions with care to avoid temperature rise of the solution and
reacted for 23 hours at the room temperature. The resultant
polyamide acid had inherent viscosity of 0.70 dl/g.
The polyamid acid solution was diluted with 266 grams of
N,N-dimethylacetamide to give rotational viscosity of 35,600
cps.
The solution thus obtained was applied on the electrolytic copper
foil as Example 1 to give the copper-clad circuit substrates having
film thickness of 35 .mu.m. The peel strength of the copper foil
was 3.6 kg/cm at the room temperature (25.degree. C.). The same
value was obtained by the solder heat resistance test for 180
seconds at 260.degree. C. or 300.degree. C.
COMPARATIVE EXAMPLE 1
The procedure of Example 4 was repeated except
2,2-bis-[4-(4-aminophenoxy)phenyl]propane was used in place of
2,2-bis-[4-(3-aminophenoxy)phenyl]propane to give polyamic acid
having inherent viscosity of 1.16 dl/g.
The polyimide powder prepared from the polyamic acid did not flow
even at 400.degree. C. under load of 500 kg.
The polyamic acid solution was diluted with 368 grams of
N,N-dimethylacetamide to give rotational viscosity of 34,200 cps.
The copper-clad circuit substrates having film thickness of 34
.mu.m were obtained by the same procedure as Example 1. Peel
strength of the copper-foil was an inferior value of 0.7 kg/cm at
the room temperature (25.degree. C.).
EXAMPLE 5-21 AND COMPARATIVE EXAMPLE 2
The procedure of Example 1 was repeated except type and quantity of
diamine, quantity of N,N-dimethylacetamide, and type and quantity
of tetracarboxylic acid dianhydride were changed to give results
described in Table 1 and 2.
Regarding the quantity of N,N-dimethylacetamide in Table 1, normal
figures indicate the quantity used for polymerization and those in
parentheses indicate the quantity further added after
polymerization to dilute the solution. When diluted, rotational
viscosity was measured after dilution. Melt viscosity was measured
at shear rate of 10.sup.3 l/second.
In the Table 1, PMDA means pyromellitic dianhydride, BTDA means
3,3',4,4'-benzophenone tetracarboxylic dianhydride, ODPA means
bis(3,4-dicarboxyphenyl)ether dianhydride and BPDA means
3,3',4,4'-biphenyl tetracarboxylic dianhydride.
EXAMPLE 22
The polyamic acid varnish obtained in Example 5 was casted on the
glass plate and heated for an hour each at 100.degree. C.,
200.degree. C. and 300.degree. C. to give a light yellow and
transparent polyimide film having thickness of 30 .mu.m. The
polyimide film had tensile strength of 13.5 kg/mm.sup.2 and
elongation of 42% in accordance with ASTM D-882. The film also had
glass transition temperature of 225.degree. C. in accordance with
TMA penetration method and the 5% by weight decrease temperature in
air of 542.degree. C. in accordance with DTA-TG method.
The polyimide film was put on the electrolytic copper foil having
35 .mu.m in thickness and was hot-pressed at 270.degree. C. for 10
minutes under pressure of 20 kg/cm.sup.2 to give flexible
copper-clad circuit substrates. Peel strength of the copper foil
was 2.7 kg/cm at the room temperature (25.degree. C.). The same
value was obtained by the solder heat resistance test for 180
seconds at 260.degree. C. or 300.degree. C.
TABLE 1
__________________________________________________________________________
Materials and Solvent Solvent Dianhydride (N,N--Dimethyl- Diamine
(g) acetamide) No. (g) (mol) (mol) (g)
__________________________________________________________________________
Example - 5 bis[4-(3-aminophenoxy)phenyl] PMDA 184.5 sulfide 21.1
40 (0.1) (0.097) Example - 6 bis[4-(3-aminophenoxy)phenyl] BTDA
214.8 sulfide 31.6 40 (0.1) (0.098) Example - 7
bis[4-(3-aminophenoxy)phenyl] ODPA 184.5 sulfide 36.6 40 (0.1)
(0.0986) Example - 8 bis[4-(3-aminophenoxy)phenyl] BPDA 205 sulfide
28.3 40 (0.1) (0.0965) Example - 9 4,4'-bis(3-aminophenoxy)biphenyl
PMDA 175.8 36.8 (0.1) 20.71 (0.095) Example - 10
4,4'-bis(3-aminophenoxy)biphenyl BTDA 103.5 18.4 (0.05) 16.1 (473)
(0.05) Example - 11 4,4'-bis(3-aminophenoxy)biphenyl ODPA 50.85 9.2
(0.025) 7.75 (271) (0.025) Example - 12
4,4'-bis(3-aminophenoxy)biphenyl BPDA 48.8 9.2 (0.025) 7.06 (206)
(0.024) Example - 13 bis[4-(3-aminophenoxy)phenyl] PMDA 182.9
ketone 21.36 39.6 (0.1) (0.098) Example - 14
bis[4-(3-aminophenoxy)phenyl] PMDA 182.9 ketone 21.36 39.6 (0.1)
(0.098) Example - 15 bis[4-(3-aminophenoxy)phenyl] BTDA 215.4
ketone 31.5 39.6 (0.1) (0.098) Example - 16
bis[4-(3-aminophenoxy)phenyl] ODPA 210 ketone 30.5 39.6 (0.1)
(0.099) Example - 17 bis[4-(3-aminophenoxy)phenyl] PMDA 195 sulfone
21.8 (823) 43.2 (0.1) (0.1) Example - 18
bis[4-(3-aminophenoxy)phenyl] BPDA 167 sulfone 28.4 43.2 (0.1)
(0.0965) Example - 19 2,2-bis[4-(3-aminophenoxy)phenyl]- PMDA 44.16
1,1,1,3,3,3-hexafluoropropane 4.273 10.36 (0.02) (0.0196) Example -
20 2,2-bis[4-(3-aminophenoxy)phenyl]- BTDA 25.2
1,1,1,3,3,3-hexafluoropropane 3.19 (8.3) 5.18 (0.01) (0.0099)
Example - 21 2,2-bis[ 4-(3-aminophenoxy)phenyl]- ODPA 24.6
1,1,1,3,3,3-hexafluoropropane 3.01 5.18 (0.01) (0.0097) Comparat.
4,4'-diaminodiphenylether PMDA 125.4 Example - 2 20.0 (0.1) 21.8
(529) (0.1)
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TABLE 2
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Properties of Polyamic Acid and Polyimide Viscosity Copper Film
Peel strength (kg/cm) melt foil and thick- solder solder inherent
rotational (poise) thickness ness room 260.degree. C. 300.degree.
C. No. (dl/g) (cps) (.degree.C.) (.mu.m) (.mu.m) 25.degree. C. 180
sec 180 sec
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Example - 5 1.0 34,000 5,200 electro- 30 2.6 2.6 2.6 (340) lytic
(35) Example - 6 1.2 67,000 " 32 2.7 2.7 2.6 Example - 7 1.1 48,500
" 33 2.9 2.9 2.9 Example - 8 0.6 2,000 " 30 2.9 2.9 2.9 Example - 9
0.60 2,100 4,700 " 35 3.0 3.0 3.0 (400) Example - 10 1.62 10,000 "
34 2.8 2.8 2.8 Example - 11 1.70 8,500 " 35 2.9 2.7 2.7 Example -
12 1.8 12,000 " 37 2.8 2.8 2.8 Example - 13 0.85 8,000 rolled 30
2.4 2.4 2.4 (35) Example - 14 0.85 8,000 electro- 30 2.9 2.9 2.9
lytic (35) Example - 15 0.78 5,000 4,800 electro- 35 2.8 2.8 2.8
(360) lytic (35) Example - 16 0.8 5,800 " 30 2.8 2.8 2.8 Example -
17 1.6 5,000 " 30 2.2 2.2 2.2 Example - 18 0.62 8,500 " 28 2.7 2.7
2.7 Example - 19 0.55 1,400 3,500 " 80 2.7 2.7 2.7 (400) Example -
20 1.1 25,000 " 35 2.8 2.8 2.8 Example - 21 0.68 3,800 " 35 2.8 2.8
2.8 Comparat. 1.5 9,000 " 30 0.5 0.5 0.5 Example - 2
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